Smelting ores, mattes, and metals for armor-plate, rails, &amp;c.



WILLIS EUGENE EVERETTE, OF TACOMA, WASHINGTON.

SMELTING ORES, MATTES, AND METALS FOR ARMOR-PLATE, RAILS, 850.

Specification of Letters Patent.

Patented Nov. 17, 1908.

Application filed May 18, 1906. Serial No. 317,595.

To all whom "it may concern:

Be it known that I, lVILLIs EUGENE EVERETTE, a citizen of the UnitedStates, and a resident of Tacoma, in the county of Pierce and State of\Vashington, have invented certain new and useful Improvements in theSmelting of Ores, Mattes, and Metals for Armor-Plate, Rails, &c., ofwhich the following is a specification.

The object of my invention, is to provide, in addition to the usualsmelting furnace processes, (as the injection of air in the furnaceunder pressure, etc.,) an improved method of producing metals, whereby,when the casting is rapidly cooled, an unusually hard metal is formed;and when the casting is slowly cooled, a soft, pliable, metal isproduced, the terms unusually hard and very pliable, being used in acomparative sense, the absolute hardness or softness differing withdifferent metals. The metals as obtained may be used as desired, forexample, if the metal be iron, it may be used for armor plate,projectiles, rails, tool metal, structural metal, and other purposes. Ifthe metal obtained be copper or other metals, they may be used for anypurposes to which they are adapted.

The method which I pursue, is very simple and direct, requiring but asingle melt. It thus does away with auxiliary processes, and enables themolten metal to be drawn off from the many kinds of ores and mattes,directly into the mold, without many of the usual and intermediate andpreliminary metallurgical processes. I accomplish these results, by achange in the normal furnace flux, by which the pig-metal, the ore, thematte, speiss, or zaffer, and any impure alloy, is reduced to a moltenmetallic state in the furnace,-preparatory to casting.

As applied to iron oxid ores, and iron carbonate ores, the usual furnacealkaline flux (which is composed of the carbonate of an alkali-i.e.limestone) always creates a difficulty which necessitates a secondaryand purifying melting, such for example, as the Bessemer, open hearth,or any other purifying process, before the metal can be run off into themold. This difficulty arises from the presence of an excess of oxygen,both in the oxid and carbonate ores, and also in the oxygen from thecarbonate of the alkaline flux-z'. e.(limestone) in the furnace charge.Take iron-oxid ore, for example, whose formula as ferric-sesqui-oxid is(F e 0 This sesqui-oxid, must be torn apart from the iron content, sothat the oxygen, disappears, and the metallic iron, remains. A carbonateof an alkali flux (as for instance, calcium in the shape of lime stone)also has an oxygen content as (CaCO,). The result of the use of acarbonate of an alkali flux, therefore, is to drive off indeterminateoxids, and replace them with fixed oxids and sub-oxids, which have to beburned off by the Bessemer process, in the metallurgy of iron and steelmanufacture. By experience and observation, I have become convinced thatthis is the case.

In the case of sulfid ores, it is preferred for the sake of economy,that the sulfur is to be driven off as far as possible-about down to a4- to 10 per cent. roast-by what is known as preliminary calciningprocess, which results in the formation of an impure oxid orealthough myimproved process, is applicable to the treatment of sulfid ores, withoutthis usual preliminary roasting.

It is well known, that castings of cast-iron and cast-copper, made bythe use of a carbonate flux, are weak, brittle, and shortlived-whencompared to wrought metal. By my improved method of direct smelting, Iobtain by a single process of melting, a particularly pure metal, andthe castings thus obtained, have nearly, if not quite, the strength anddurability of wrought metal. To accomplish these results, I use afurnace flux composed of the cyanid of an alkali, and carbon, in anyform well mixed together. Any cyanid of an alkali may be used. Thecheapest alkaline cyanid being cyanid of calcium; but cyanid of potash,or cyanid of soda, or cyanid of magnesium, may be used, where the valueof the casting warrants such use. Although a borate of an alkali, and afluorid of an alkali, may be used as a flux, I prefer to use the cyanidof an alkali, for many important reasons. \Vhile it is a knownmetallurgical fact, that the cyanid of an alkali has been used as areducing agent, it is not known that it has been heretofore used forsmelting furnace processes and in conjunction with carbon, in thescience of metallurgy.

The proportions of the cyanid to the carbon content of the furnacecharge, will vary somewhat with the character of the ore, to which it isto be appliedboth as to the metallic content, and whether the ore is asulfid,

oxid, or carbonate. For ordinary ores, the flux should contain, fromequal parts of carbon and cyanid, to a proportion of about two parts ofcarbon to three parts of cyanid. IVhere the metallic content of the oreor matte is high, the amount of cyanid will be less; and where themetallic content is low,

the amount of cyanid that is required will be higher. In the case of anoxid or carbonate ore, the proportion of carbon and cyanid, will be morenearly equal. In the case of sulfid ores, the cyanids will be in excessof the carbon in the furnace charge.

In the smelting of iron-ores, I prefer to use from sixty to seventy percent. of flux and fuel, to thirty per cent. of the ore, according to therefractory condition of the ore: it being understood, that when thepercentage of the flux, is increased relatively to the ore, it isbecause the ore being more refractoryrequires more additional cyanid ofan alkali.

In the case of lead ores, copper ores, silver ores, and tin oreswhen assulfidsand in the case of gold ore, as a telluridthe maximum amount ofcyanid is then always required. But, when the gold, silver, and copper,appear in the metallic state in the ore, along with silicious or otherclass of rocks, then the smaller amount of cyanid will suffice. All ofthese ores may be economically treated by my improved process ofsmelting; and so may nickel, aluminum, and other ores.

Mattes, alloys impure, pig-metal, and im pure metals, may be purified,and hardened or toughened as desired, by melting them with my cyanidflux, and then cooling rapidly or slowly, according to whether hardnessor toughness is principally desired.

After the ore-charge and cyanid fiux, are put in the furnace, thetemperature should be raised to about 3000 Fahr. for iron,

nickel, cobalt, or manganese ores, but should not exceed 2500 Fahr. forgold, silver, copper, lead, and tin ores. In from one half to twohours-depending on the quantity of air admitted as atmospheric oxygen tocombine with the carbon and sulfur content of the furnace charge-themetal should be 'ready to porn into the molds. The remaining step of myprocess, is the casting of the molten metaland in this connection I havefound, that when a hard casting is required, the metal should be cooledas rapidly as possible. And that when tough, pliable, tenacious metal isrequired, the cooling should be very slowly performed. This greatdifference which results from the rapid or slow cooling of the melt,seems to arise from the fact, that the ebullition caused by the cyanogenpresent in the molten cyanid flux, separates the metal very much moreperfectly from impurities, than is the case with the usual furnace fluxas a carbonate of an alkalithe impurities either escaping as gases, orpassing into the waste or furnace slag.

I therefore claim 1. An improved method of smelting ores, mattes,alloys, and metals, which consists in reducing and refining the same ina furnace, by means of a flux that is composed of carbon and the cyanidof an alkali.

2. An improved method of smelting, ores, mattes, alloys, and metals,which consists in reducing the same in a furnace, by means of a flux,that is composed of carbon and the cyanid of an alkali, and in castingthe refined metal therefrom, in suitable molds, thereby hardening andtoughening it, substantially as described in these hereinspecifications.

WILLIS EUGENE EVERETTE.

WVitnesses ANNA H. VAN HovnNPaRe, WV. P. PREBLE, Jr.

